Keratocystic Odontogenic Tumor (Odontogenic Keratocyst)



Keratocystic Odontogenic Tumor (Odontogenic Keratocyst)


Brenda L. Nelson, DDS, MS





Key Facts


Terminology



  • Odontogenic keratocyst (OKC)


  • Distinct developmental odontogenic cyst that may be locally aggressive


Etiology/Pathogenesis



  • Arise from cells of dental lamina


  • Nevoid basal cell carcinoma syndrome (Gorlin syndrome) is associated with multiple odontogenic keratocysts


Clinical Issues



  • Predilection for mandible


  • Multiple recurrences


  • Ovarian fibromas


Image Findings



  • Well-defined, unilocular radiolucency


  • Smooth, corticated borders


Macroscopic Features



  • Thin, friable soft tissue


  • Keratinaceous debris


Microscopic Pathology



  • Epithelial lining


  • 6-8 cells thick


  • Lacks rete ridges


  • Parakeratotic epithelial cells


  • Wavy or corrugated surface


  • Basal layer shows palisading and hyperchromicity


  • Inflammation may alter characteristic histology


Top Differential Diagnoses



  • Orthokeratinized odontogenic cyst


  • Dentigerous cyst







Axial T2 MR reveals a mandibular odontogenic keratocyst as a high signal, expansile mass within the coronoid process image and ramus image. Internal septation image is noted.






Cells of the basal layer of the epithelium show characteristic palisading and hyperchromaticity image. The epithelium is 6-8 cells thick and demonstrates a wavy, parakeratinized surface image.


TERMINOLOGY


Synonyms



  • Odontogenic keratocyst (OKC)


  • Primordial cyst


  • Odontogenic keratocystoma


Definitions



  • Distinct developmental odontogenic cyst that may be locally aggressive


ETIOLOGY/PATHOGENESIS


Histogenesis



  • May arise from cells of dental lamina


  • May arise from extensions of basal cells from overlying oral epithelium


Inherited Condition



  • Nevoid basal cell carcinoma syndrome (NBCCS; Gorlin syndrome)



    • Autosomal dominant trait



      • High penetrance, variable expression


    • Spontaneous mutations


    • 9q22, involving PTCH gene


CLINICAL ISSUES


Epidemiology



  • Incidence



    • 4-12% of developmental cysts


  • Age



    • Wide range, usually 10-40 years


    • Cysts found at earlier age in those with NBCCS


  • Gender



    • Slight male predilection


  • Ethnicity



    • Caucasians affected most commonly

Tags:
Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Keratocystic Odontogenic Tumor (Odontogenic Keratocyst)

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